Passive temperature modulation systems and devices employing solid phase-change materials

ABSTRACT

A heating or cooling system based on solid materials capable of absorbing or releasing heat during a phase change is provided. The system comprises solid members that absorb or release heat during a phase change, locking members to mechanically lock in a desired phase, and a heat exchange medium.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation-In-Part and Divisional of U.S. patent application Ser. No. 13/076,257 filed Mar. 30, 2011, now allowed, which is incorporated in its entirety by reference herein.

STATEMENT REGARDING RIGHTS TO INVENTION MADE UNDER FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT

This invention was made with Government support under Contract DE-AC05-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.

FIELD OF THE INVENTION

The invention generally relates to storing and releasing energy using solid-state materials and more particularly relates to heating or cooling using solid-state materials.

BACKGROUND OF THE INVENTION

In a variety of activities there is a need to maintain temperatures of certain items or spaces within in preselected range while the ambient temperature fluctuates. In many cases, these items or spaces exist in regions where electricity and other energy sources are generally unavailable or unreliable. A variety of mechanisms have been utilized and developed to provide selected heating or cooling functions to a particular space or item. However, each of these other systems is characterized by problems that need to be accounted for. For example, ice can be used for cooling, but ice melts and requires extreme temperatures for re-freezing. Refrigeration compressors, on the other hand, are currently the dominant mechanism used for cooling. However, they have moving parts that wear out, they require an external power supply, and they consume refrigerant fluids that are often strong sources of greenhouse gasses. A new system is needed for alternatively providing passive cooling and/or heating, for example, in remote desert environments where electricity is unavailable or unreliable.

Additional advantages and novel features of the present invention will be set forth as follows and will be readily apparent from the descriptions and demonstrations set forth herein. Accordingly, the following descriptions of the present invention should be seen as illustrative of the invention and not as limiting in any way.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide repeatable cooling or heating cycles in environments where electricity may not be available. The present invention comprises at least one solid member made of a material that undergoes a phase change when heat is released or absorbed, a locking member that selectively holds the solid member in a desired phase, a heat exchange medium in contact with the at least one solid member, and a chassis to hold the at least one solid member in mechanical communication with the locking member. In this embodiment, the at least one solid member is held in a desired phase by the locking member and is selectively released to permit transition of the at least one solid member from one phase to the other phase to allow the solid member to absorb or release heat in the heat exchange medium.

In another embodiment, the present invention comprises at least one solid member made of a material that undergoes a phase change from a first phase to a second phase when heat is absorbed or released and a locking member that selectively holds the at least one solid member in a desired phase. In this embodiment, the at least one solid member is held by the locking member in the second phase and is selectively released to permit transition of the solid member from the first phase to the second phase resulting in the solid member absorbing or releasing heat.

In another embodiment, the invention comprises a plurality of solid members made of a material that undergoes a phase change from a first phase to a second phase, thereby absorbing heat from ambient air in contact with the solid members, one or more locking members that holds at least one of the solid members in the first phase, wherein the locking members can be selectively released at a predetermined time allowing the solid members to absorb heat from the ambient air, a chassis to hold the solid members in mechanical communication with the locking members, a plurality of wheels physically coupled with the chassis to support the chassis, thereby allowing the system to be reversibly moved from a first preselected location wherein the ambient air is below about 60° F. to a second preselected location wherein the ambient air is above about 75° F. In this embodiment, in the first preselected location the solid members transition to the first phase, thereby releasing heat into the ambient air, and the solid members are held in the first phase by the locking members; and in the second preselected location one or more locking members can be selectively released to allow transition of at least one of the solid members to the second phase, thereby allowing the solid members to absorb heat from the ambient air.

In other embodiments of the invention, the heat exchange medium is selected from the group consisting of air, water, or alcohol. In another embodiment of the invention, the at least one solid member has a heat absorption capacity of about 100,000 kJ to 200,000 kJ. In another embodiment, the at least one solid member is in the form of a rod, a sheet, a tube, or a block. In another aspect, the at least one solid member is comprised of a nickel titanium alloy.

The purpose of the foregoing abstract is to enable the United States Patent and Trademark Office and the public generally, especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

Various advantages and novel features of the present invention are described herein and will become further readily apparent to those skilled in this art from the following detailed description. In the preceding and following descriptions, preferred embodiments of the invention are shown and described by way of illustration of the best mode contemplated for carrying out the invention. As will be realized, the invention is capable of modification in various respects without departing from the invention. Accordingly, the drawings and description of preferred embodiments set forth hereafter are to be regarded as illustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an embodiment of the present invention.

FIG. 2 is a perspective side view of a system of the present invention.

FIG. 3A is an exploded view of a locking mechanism of the embodiment shown in FIG. 2.

FIG. 3B shows the locking mechanism of FIG. 3A in an engaged or locked arrangement.

FIG. 3C shows the locking mechanism of FIG. 3A in a disengaged or unlocked arrangement.

FIG. 4 is a view of an embodiment of the present invention in combination with an air circulation device.

FIG. 5A illustrates the portability of the invention.

FIGS. 5B-5C are top views showing the utility of the invention with portability.

FIGS. 6A-6B show perspective views of the system with front and rear doors.

FIGS. 6C-6D show top views of a system of the invention with integrated front and rear doors for cooling an enclosed space.

FIGS. 7A-7B show top views of a system of the invention for heating an enclosed space.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a system for heating or cooling that employs solid-state rods that release or absorb latent heat during a phase transition. The present invention addresses a need for a heating or cooling system that uses no electricity, thus allowing, for example, for remote deployment. The present invention provides a solution for cost effective, energy efficient, and environmentally friendly operation compared to prior art since it does not require an external energy source such as a generator, fuel, or electrical power. As a cooling system, the invention is useful in a desert environment where large variations exist between daytime and nighttime temperatures. In the following description, embodiments of the present invention are shown and described by way of illustration of the best mode contemplated for carrying out the invention. It will be apparent that various modifications and alternative constructions to the present invention may be made. Therefore the description should be seen as illustrative and not limiting. The present invention is intended to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.

FIG. 1 shows a first view of one embodiment of the present invention. A solid member 2 is shown made of a material that undergoes a change from a first phase to a second phase when heat is absorbed or released resulting in a change in temperature (ΔT). The solid member 2 is held in a desired phase by a locking member 4, which is selectively released to permit transition of the solid member 2 from one phase to the other phase to allow the solid member 2 to absorb or release heat in a heat exchange medium 6. Unless otherwise stated, it will be assumed that transition from the first phase to the second phase releases heat and transition from the second phase to the first phase absorbs heat. However, no limitations are intended.

Solid member 2 includes a bi-metal alloy of nickel and titanium (NiTi). The NiTi alloy has a density of about 6400 kg/m³ and a latent heat up to about 21 kJ/kg. The NiTi alloy includes an atomic ratio for each metal of the bi-metal alloy given by [(50+X):(50−X)], where X=0 to 10. In a preferred embodiment, the composition of the bimetal alloy is about 50% Ni and about 50% Ti. Solid member 2 undergoes a phase transition at a temperature of about 60° F. In other embodiments, the phase transition temperature may be as low as about 40° F. and as high as about 80° F. After undergoing the change from the first phase to the second phase during which heat is released, the length of the solid member 2 decreases by about 5%-7%, after which the locking member 4 can be engaged to lock the solid member 2 into the second phase by mechanical stress. In other embodiments, length of the solid member 2 may decrease by up to about 10% in the second phase compared to the length in the first phase.

In a preferred embodiment, the solid member 2 is in the shape of a cylindrical rod. A cylindrical rod shape is preferred because it lacks sharp corners or edges along its length that may lead to early fatigue of the solid member 2. The solid member 2 has a length-to-diameter ratio equal to or greater than about 10. In a preferred embodiment, the solid member 2 has a length of about 90 cm in the first phase and a diameter of about 4 cm. The volume the solid member 2 is therefore about 1130 cm³ in the first phase.

The solid member 2 may include various shapes suitable for embodiments of the present invention. Shapes suitable for use include: rods, sheets, tubes, pipes, blocks, or other structured forms. Structured forms may be fashioned by various processes including, but not limited to, for example, pressing, pelletizing, casting, extruding, stretching, bending, twisting, or combinations of these various processes. Different shapes may be desirable depending on the needs of the user or the particular embodiment. Thus, the description is not intended to be limiting.

The NiTi alloy is polycrystalline. Typical crystal grain sizes of the solid member 2 range from several microns to several hundreds of microns, although this is not intended to be limiting. The preferred crystal grain orientation of the solid member 2 is in the [111] direction, i.e. along the axial direction of the rod. It is known to those with ordinary skill in the art that this grain orientation yields a higher coefficient of performance (COP). It is further known to those with ordinary skill in the art that the manufacture process of the solid member 2 affects the grain size and orientation.

The manufacturing process of the solid member 2 includes, but is not limited to, casting, annealing, sizing, and cold drawing. The solid member 2 is formed by a method of induction melting and/or arc melting, preferably in a casting crucible devoid of carbon and in an environment devoid of oxygen. After melting, the alloy is homogenized at a temperature of about 900° C. to 1200° C. for about 2 to 4 hours. The alloy is then allowed to air cool. The alloy is then subject to cold drawing to form a rod. The rod may need an additional heat treatment to prompt the shape memory effect and to adjust the phase transition temperature and latent heat. Carbon included during the melting process as an impurity may form titanium carbide (TiC). It is generally desirable to prevent the formation of TiC during manufacture, because TiC inclusions tend to reduce the fatigue life of the final solid member 2. The control and limitation of carbon during manufacture is generally accomplished through control of the carbon content of the casting crucible. Oxygen included during the melting process as an impurity may form titanium oxide (TiO). It is generally desirable to prevent the formation of TiO during manufacture, because TiO inclusions tend to reduce the fatigue life of the solid member 2. The control and limitation of oxygen during manufacture is accomplished by controlling the gas environment of the furnace. In a preferred embodiment, carbon impurities are limited to a level no higher than about 500 ppm. In a preferred embodiment, oxygen impurities are limited to a level no higher than about 500 ppm. In alternative embodiments, carbon impurities are limited to about 4000 ppm and oxygen impurities are limited to about 4000 ppm.

The solid member 2 may be constructed of, for example, alloys and metal-containing alloys that provide preselected changes in enthalpy for intended applications. In some embodiments, alloys include metals and materials including, but not limited to, e.g., nickel (Ni), aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), strontium (Sr), zirconium (Zr), palladium (Pd), hafnium (Hf), platinum (Pt), bismuth (Bi), carbon (C), oxygen (O), including combinations of these materials. In some embodiments, the alloy is a bi-metal alloy. In other embodiments, the alloy contains multiple metals or is a multi-component alloy. Other alloys are within the scope of the invention. For example, solid member 2 may be comprised of alloys such as, for example, CuAlNi, CuZnAl, NiMnGa, or NiMnSn. Thus, no limitations are intended.

The locking member 4 is in mechanical communication with the solid member 2 such that the locking member 4 is able to retain the solid member 2 in the second phase when the solid member 2 is of decreased length compared to the first phase. When released, the locking member 4 is able to allow the length of the solid member 2 to increase as the solid member 2 transitions to the first phase. The solid member 2 generates about 800 MPa of stress when secured by the locking member 4 in the second phase. In a preferred embodiment in which the solid member 2 is a cylindrical rod with a diameter of 4 cm and a cross sectional area of about 12.56 cm², the force required to retain the solid member 2 in the second phase is about 10000 Newtons. In other embodiments, the force required to retain the solid member 2 in the second phase may be affected by the properties of the solid member 2. For example, as known by those with ordinary skill in the art, such properties may include, but are not limited to, the cross-sectional area, composition of the metallic alloy, inclusion of impurities, grain size, grain direction, and combinations of these various properties and factors.

The heat exchange medium 6 is air that is in thermodynamic contact with the solid member 2 thereby absorbing or releasing heat from the solid member 2 and undergoing a change in temperature ΔT. In other embodiments, the heat exchange medium 6 may be water, organic liquids such as ethanol, or other heat exchange media or combinations thereof. No limitations are intended.

FIG. 2 shows another embodiment of the present invention. A chassis 8 with a left side 18, a right side 20, a top 22, and a bottom 24 assembled at substantially right angles to define an interior region 10. Interior region 10 houses at least one solid member 2, which is constrained within the chassis 8 by solid member supports 12. In this embodiment, a locking member 4 is comprised of a locking handle 14, a connection beam 30, and a loading member 31. A preferred embodiment of the locking member 4 is described in reference to FIGS. 3A-3C. In a preferred embodiment, wheels 16 may be mounted to the bottom of the chassis 24 to allow portability. In other embodiments, wheels 16 may be optional.

Solid member supports 12 are in mechanical communication with the solid member 2 to hold the solid member 2 in a predetermined location and orientation within the interior region 10 of the chassis 8. Solid member supports 12 may be made of steel (e.g., stainless steel), aluminum, plastic, other rigid supporting materials, or combinations of these materials.

In a preferred embodiment, the solid member supports 12 provide a means to prevent the solid member 2 from buckling, deforming, warping, bending, or otherwise deviating from a preferred orientation and/or shape while under stress while locked in the second phase by the locking member 4. The solid member supports 12 may attach to the top 22 and the bottom 24 of the chassis 8. The solid member supports 12 are in mechanical communication with a plurality of solid members 2. Each solid member 2 is in mechanical communication with a plurality of solid member supports 12.

In an alternative embodiment, the solid member supports 12 are in mechanical communication with at least one solid member 2. In an alternative embodiment, each solid member 2 is in mechanical communication with at least one solid member support 12. In other embodiments, the solid member supports 12 are attached to any one or combination of the top 22, bottom 24, and one or more sides 18 and 20 of the chassis 8. No limitations are intended.

In the system illustrated in FIG. 2, the system is comprised of about 50 NiTi solid members 2, which results in a total heat capacity of up to about 151,000 kJ. In this embodiment, the system should have the capacity to meet about 50% of the cooling demand of a 300-600 square-foot room for about 12 hours. Further, the solid members 2 are configured in 5 rows of 10 units per row in the chassis 8. The solid members 2 are supported by two sets of solid member supports 12. Five (5) of the solid members 2 can be locked and released with a single locking member 4. In other embodiments, the system is comprised of a preselected number of solid members 2 that provide a predetermined total heat capacity. In other embodiments, the solid members 2 may be arranged in a predetermined orientation and spacing within the chassis 8. No limitations are intended. In other embodiments, various sizes and numbers of solid members 2 can be used based on the needs of the user. For example, if more rapid cooling is required, a different geometric shape or size of solid members 2 with a greater surface-to-volume ratio may be used. As another example, more cooling capacity may require a greater number or larger sizes of solid members 2. Thus, the description is not intended to limit the various combinations of numbers, shapes, and sizes of solid members 2 that can be implemented based on the needs of the user.

In the system illustrated in FIG. 2, the chassis 8 is about 30 cm deep, about 60 cm wide, and about 100 cm tall. The interior region 10 includes suitable dimensions to accommodate the solid members 2, the solid member supports 12, and various components of the locking members 4. The chassis 8 is comprised of a steel reinforced frame, with left 18 and right 20 sides, a top 22, and a bottom 24 comprised of mild steel sheets with a thickness of about 3 mm to about 5 mm. In alternative embodiments, the left 18 and right 20 sides, top 22, and bottom 24 are comprised of mild steel sheets with a predetermined thickness adequate to withstand the stress of the solid members 2 when locked in the second phase. In alternative embodiments, the left 18 and right 20 sides, top 22, and bottom 24 are comprised of a predetermined material with a predetermined thickness adequate to withstand the stress of the solid members 2 when locked in the second phase. In a preferred embodiment, the chassis 8 is of sufficient strength to support at least the weight of a preselected number of solid members 2, solid member supports 12, and locking members 4. The chassis 8 is also of sufficient strength to withstand the stress of a preselected number of solid members 2 locked in the second phase.

In another embodiment, the chassis 8 may be in the form of a rack with a frame (not shown) with no top and no bottom, which may, for example, be mounted to a wall, floor, or ceiling, or which may, for example, be leaned against a wall or held upright by an A-frame. In other embodiments, the chassis 8 may be a carriage, cabinet, case, body, chest, or trunk. Other modes of containment deemed desirable for different embodiments may be used. No limitations are intended.

In other embodiments, various numbers of solid members 2 can be locked and unlocked by components of each locking member 4. For example, as shown in FIG. 2, each locking handle 14 in concert with other components of the locking members 4 can lock and unlock a plurality of solid members 2. In other embodiments, each locking handle 14 in concert with other components of the locking members 4 can lock and unlock one or more solid members 2. However, the description is not intended to limit the number of solid members 2 that can be engaged by the locking members 4. For example, a single solid member 2 may be in mechanical communication with multiple locking members 4, but is not intended to be limited thereto.

In the instant embodiment, chassis 8 includes an open front, which allows the heat exchange medium 6 to be in contact with each of the solid members 2 permitting exchange of latent heat as detailed herein.

In a preferred embodiment, the invention may have four wheels 16 attached at or near each corner of the bottom 24 of the chassis 8 to provide mechanical support or to allow portability, but is not intended to be limited thereto. To support the load of the invention in the preferred embodiment, each of the four wheels 16 may have a load capacity of at least about 2000 kg. In an alternate embodiment, the invention may have three or more wheels 16 attached to the bottom 24 of the chassis 8. In various embodiments, the wheels 16 may swivel, and/or the wheels 16 may have a locking mechanism that can be engaged to prevent undesired motion.

In another embodiment, the wheels 16 may be attached to any side or combination of sides of the chassis 8. For example, but not intended to be limiting, an embodiment of the invention may have wheels 16 attached to the left side 18 of the chassis 8. In this example, the chassis 8 may be oriented on the wheels 16 such that the solid members 2 are oriented vertically. In another embodiment of the invention, the wheels 16 may be attached to any one or more of sides of the chassis 8 to allow flexibility in orientation or portability of the chassis 8. However, no limitations are intended.

FIG. 3A illustrates a preferred embodiment of the locking member 4. The locking member 4 may include a locking handle 14, a threaded bar 26, a hole 28 through the right side 20 of the chassis 8 to allow passage of the threaded bar 26, a connection beam 30 mounted to the exterior surface of the right side 20 of the chassis 8, and a loading member 31 in mechanical communication with the threaded bar 26. The connection beam 30 may include a threaded hole 29 designed to mate with the threaded bar 26.

As illustrated in FIG. 3B, the locking handle 14 can be turned in a predetermined direction to reversibly engage the threaded bar 26 with the threaded hole 29 thereby coming into mechanical communication with the loading member 31, which translates the loading member 31 in the direction along the longitudinal axis of the hole 28 and the threaded hole 29 until the loading member 31 is in contact with the solid member 2 thereby locking the solid member 2 into the second phase. This state is defined as the engaged or locked position.

As illustrated in FIG. 3C, the solid members 2 can be released by turning the locking handle 14 in the opposite direction thereby translating the loading member 31 and threaded rod 26 into a state defined as the disengaged or unlocked position, thus allowing the solid member 2 to elongate and transform to the first phase. The loading member 31 is designed to engage with the full cross-section of the solid member 2 thereby preventing damage to the solid member 2 caused by, for example, but not limited to, partial loading or stress concentration.

In alternative embodiments, not intended to be limiting, the locking members 4 may be arranged to engage through the left side 18 of the chassis 8 as described previously in reference to FIG. 2, or both the left side 18 of the chassis 8 and the right side 20 of the chassis 8 (described previously, for example, in reference to FIG. 2).

In another alternative embodiment, the solid members 2 may be oriented vertically and the locking members 4 arranged on the top 22 of the chassis 8. No limitations are intended.

In a preferred embodiment, a 90 cm long solid member 2 in the form of a cylindrical rod will change in length by about 4 cm to 7 cm when transitioning from the first phase to the second phase. The threaded bar 26 is of a predetermined length such that the threaded bar 26 can travel at least 4 cm to at least 7 cm to allow the solid member 2 to be locked into the second phase when the threaded bar 26 is in the locked position and, further, to allow the solid member 2 to transform into the first phase when the threaded bar 26 is in the unlocked position. In an alternative embodiment, the threaded bar 26 is of a predetermined length such that the threaded bar 26 can travel a sufficient distance to move between the locked position and the unlocked position, which allows a solid member 2 (with a predetermined change in length during phase transition) to transition from the second phase to the first phase.

The solid member 2 is held fixed at one end by a solid member support 12 and in mechanical communication with the left side 18 of the chassis 8, as detailed previously in reference to FIG. 2, such that the change in length of the solid member 2 experienced during a phase transition is expressed only at the other end of the solid member 2, thus allowing the locking member 4 to lock and unlock the solid member 2 into the desired phase. In an alternative embodiment, not intended to be limiting, the solid member 2 is held fixed at one end by a bolt, rod, clasp, or other locking mechanism. In an alternative embodiment, locking members 4 are in communication with both ends of each solid member 2.

In an alternative embodiment, a loading member 31 is mechanically affixed to the end of the solid member 2 such that when the locking handle 14 is in the locked position the threaded bar 26 is in mechanical communication with the loading member 31 with force transmitted through the loading member 31 to the entire cross-section of the solid member 2 to lock the solid member 2 into the second phase. Further, in the unlocked position, the loading member 31 remains mechanically affixed to the solid member 2.

In an alternative embodiment, the connection beam 30 is mounted to the interior surface of the right side 20 of the chassis 8. In an alternative embodiment, hole 28 is a threaded hole designed to mate with the threaded bar 26. Such an embodiment may be desired if, for example, the right side 20 of the chassis 8 is a predetermined thickness such that the hole 28 can accommodate enough threads to adequately engage the threaded bar 26. In such an embodiment, the connection beam 30 may be optional. In a preferred embodiment, the locking member 4 is comprised of steel. In alternative embodiments, the locking member 4 is comprised of one or more of, but not limited to, steel, stainless steel, aluminum, plastic, or any other predetermined rigid material.

Other embodiments of the invention can use different types of locking members 4. For example, but not intended to be limiting, the locking member 4 may be comprised of a sliding apparatus, such as comprising solid rods, sheets, or pins, which may be used to engage the loading member 31, thereby locking the solid members 4 into the first phase. Further, the solid members 4 can be unlocked by removing the sliding apparatus. Other locking members include, but are not limited to, those that incorporate latches, bolts, screws, hasps, or cams.

FIG. 4 illustrates another embodiment of the present invention. In this embodiment, a heat exchange medium circulation device 32 can be used to circulate a heat exchange medium 6 through the interior region 10 of the chassis 8. The top 22, left side 18, right side 20, and bottom 24 of the chassis 8, and other components including the wheels 16, loading members 31, and solid member supports 12 have been described previously, for example, in reference to FIG. 2.

In a preferred embodiment, the heat exchange medium 6 is air, and the heat exchange medium circulation device 32 forces the air 6 into or out of the interior region 10 such that the air is in thermal contact with at least one solid member 2 before emerging from the interior region 10.

In a preferred embodiment, the heat exchange medium circulation device 32 is a propeller blade fan. In alternative embodiments, the heat exchange medium circulation device 32 may be, but is not intended to be limited to, an automatic or electric powered device such as a revolving blade fan, a centrifugal fan, a cross-flow fan, or any other automatic device for moving or circulating air.

In other embodiments, the heat exchange medium circulation device 32 may be, but is not intended to be limited to, a manual device such as a bellows, a fan blade rotated by a foot-driven belt, a hand-held fan made of a material such as paper or feathers, or any other manually-powered device for moving or circulating air. In alternative embodiments, air 6 can be forced into one side of the chassis 8 and back out an adjacent side or back out the same side.

In an alternative embodiment, the invention may be completely passive and rely on natural convective motion of air 6 through the interior region 10. In other embodiments, the heat exchange medium circulation device 32 may be a device that circulates water, organic liquids such as ethanol, or other heat exchange media or combinations thereof. No limitations are intended.

FIG. 5A illustrates another embodiment of the present invention. In this embodiment, the chassis 8 is of a portable design which includes wheels 16. The chassis 8, with sides 18 and 20, top 22, and bottom 24, loading members 31, connection beams 30, interior region 10, solid members 2, solid member supports 12, and locking handles 14 have been described previously, for example, in reference to FIG. 2.

As illustrated in FIG. 5B, during the nighttime, the chassis 8 (here with top 22 and locking handles 14 showing) may be moved from within an enclosed space 34 to an outside location when the outdoor temperature is below the phase change temperature of the solid members (described previously in reference to FIG. 2), which allows the solid members to release absorbed heat to a heat exchange medium 6 and undergo a phase transition to the second phase, after which the locking members (described previously in reference to FIG. 2) can be engaged.

During the day, as illustrated in FIG. 5C, the chassis 8 (again with top 22 and locking handles 14 showing) may be moved from an outside location into an enclosed space 34 where the ambient temperature is above the phase change temperature and where cooling is desired. In the enclosed space 34, locking handles 14 can be selectively disengaged allowing the solid members (described previously in reference to FIG. 2) to transform to the first phase thus absorbing heat from a heat exchange medium 6 when cooling is desired.

In another embodiment illustrated in FIG. 6A and FIG. 6B, the chassis 8 (with top 22 and locking handles 14 shown, and with wheels 16 attached for transport) has at least one back door 36 and at least one front door 38 oriented vertically and placed on opposite sides of the chassis 8. In FIG. 6A, the back door 36 is open and the front door 38 is closed. With the back door 36 open, the interior region (not shown) and internal components (not shown) of the chassis 8 may be exposed allowing for movement of a heat exchange medium, as detailed herein.

In FIG. 6B, the back door 36 to chassis 8 (with top 22, bottom 24, and a locking handle 14 showing, and wheels 16 attached for transport) is closed and the front door 38 is open. When front door 38 to chassis 8 is open, the interior region 10 is exposed, allowing solid members 2, solid member supports 12, and loading members 31 to be accessed, and for movement of a heat exchange medium (not shown, described previously in reference to FIG. 5C) when cooling is desired.

In FIG. 6C and FIG. 6D, the utility of doors 36 and 38 on chassis 8 (with top 22 showing) is illustrated when the invention is used to cool an enclosed space 34. The chassis 8 may be placed within or in lieu of an outside wall 40 of an enclosed space 34. Doors 36 and 38 of the chassis 8 provide a means for selectively exposing the solid members (not shown) (described in reference to FIG. 2) to a heat exchange medium 6 such as outdoor or indoor air by allowing an operator to selectively open one of the doors and close the other door. For example, FIG. 6C depicts a situation when a phase change for the solid members to the second phase is desired during the night. The operator can open back door 36 and close front door 38 thereby exposing the solid members to the cool outdoor nighttime air 6 thus allowing the solid members to release heat and transform back to the second phase, after which the locking members (described previously in reference, for example, to FIGS. 3A-3C) can be engaged.

FIG. 6D (with top 22 of chassis 8 showing) depicts a situation when cooling is desired within an enclosed space 34 during the day. The operator can open front door 38 and close back door 36 of chassis 8 to expose the solid members 2 (not shown) (described in reference to FIG. 2) to warm air 6 within the enclosed space 34. When the locking members 4 (not shown) (described previously in reference to FIGS. 3A-3C) are selectively disengaged, cooling is provided as the solid members absorb heat and transform from the second phase to the first phase.

In another embodiment, not intended to be limiting, both doors 36 and 38 may be opened simultaneously. For example, opening both doors on a warm, breezy day may allow outside air to pass through the interior region (not shown) to make thermal contact with the solid members 2 (not shown) (described in reference to FIG. 2) and to enter the enclosed space 34 where cooling is desired, thereby providing fresh, cool air to the occupants.

In other embodiments of the invention, the doors 36 and 38 may be oriented horizontally such that they swing outward and upward from the chassis 8. Other embodiments may include, but are not intended to be limited to, doors of any orientation that are: swinging doors, sliding doors, folding doors, or roll-up doors. Other embodiments may employ insulated doors to minimize undesired heat transfer through a closed door.

FIGS. 7A-7B show another embodiment of the system of the invention for heating an enclosed space 34. An application of this embodiment might be a desert environment where nighttime temperatures are cooler than is comfortable for a person and below the phase change temperature of the solid members 2 (not shown) (described in reference to FIG. 2). In this embodiment, solid members could be locked into the first phase then selectively unlocked to allow transition to the second phase when heating is desired.

For example, FIG. 7A depicts a situation at night when warming may be desired in an enclosed space 34. The chassis 8 (with top 22 and locking handles 14 showing) may be moved into the enclosed space 34 such that the solid members 2 (not shown) (described in reference to FIG. 2) are exposed to a heat exchange medium 6 such as cool indoor air allowing the solid members to be selectively unlocked to release heat that heats the indoor air, and transitions the solid members to the second phase.

FIG. 7B further depicts a situation during the day when outdoor temperatures are higher than the phase change temperature of the solid members 2 (not shown) (described in reference to FIG. 2). The chassis 8 (with top 22 and locking handles 14 showing) may be moved outdoors such that the solid members are exposed to warm outdoor air allowing the solid members to absorb heat and transition to the first phase, after which the solid members can be locked into the first phase by the locking members 4 (not shown) (described previously, for example, in reference to FIGS. 3A-3C). In this embodiment, the locking members may be of various constructions in order to lock the solid members into the first phase. For example, but not intended to be limiting, the locking member may lock the solid members into a stressed, twisted orientation by application of torque or into an elongated orientation by application of grasping or pulling force. This description is not intended to limit the types of locking members or solid members that can be implemented in various embodiments for heating.

While various preferred embodiments of the invention are shown and described, it is to be distinctly understood that this invention is not limited thereto but may be variously embodied to practice within the scope of the following claims. From the foregoing description, it will be apparent that various changes may be made without departing from the spirit and scope of the invention as defined by the following claims. 

What is claimed is:
 1. A system for absorbing and releasing heat, comprising: at least one solid member made of a material that undergoes a phase change from a first phase to a second phase when heat is absorbed or released; a locking member that selectively holds the at least one solid member in a desired phase; and a heat exchange medium in contact with the at least one solid member; whereby the at least one solid member is held in a desired phase by the locking member and is selectively released to permit transition of the at least one solid member from one phase to the other phase to allow the solid member to absorb or release heat in the heat exchange medium.
 2. The system of claim 1, wherein the heat exchange medium is selected from air, water, or alcohol.
 3. The system of claim 1, wherein the system comprises a plurality of solid members.
 4. The system of claim 3, wherein each solid member is in mechanical communication with one locking member.
 5. The system of claim 1, wherein the at least one solid member has a heat absorption capacity of about 100,000 kJ to 200,000 kJ.
 6. The system of claim 1, wherein the at least one solid member is in the form of a rod, a sheet, a tube, or a block.
 7. The system of claim 1, wherein the at least one solid member is comprised of a nickel titanium alloy.
 8. The system of claim 1, wherein the at least one solid member transforms from one phase to the other phase at a temperature of about 60° F. to about 75° F.
 9. The apparatus of claim 1 further comprising a chassis, wherein the at least one solid member is held to be in mechanical communication with the locking member by the chassis.
 10. An apparatus for absorbing and releasing heat, comprising: at least one solid member made of a material that undergoes a phase change from a first phase to a second phase when heat is absorbed or released; and a locking member that selectively holds the at least one solid member in a desired phase; whereby the solid member is held by the locking member in the second phase and is selectively released to permit transition of the solid member from the first phase to the second phase resulting in the solid member absorbing or releasing heat.
 11. The apparatus of claim 10, wherein heat is absorbed or released from a heat exchange medium.
 12. The apparatus of claim 11, wherein the heat exchange medium is selected from the group consisting of: air, water, or alcohol.
 13. The apparatus of claim 10, further comprising a chassis, wherein the at least one solid member is held to be in mechanical communication with the locking member by the chassis.
 14. The apparatus of claim 13, wherein the chassis includes a plurality of wheels that are physically coupled to the chassis to support the chassis.
 15. The apparatus of claim 10, wherein the at least one solid member is in the form of a rod, a sheet, a tube, or a block.
 16. The apparatus of claim 10, wherein the at least one solid member has a heat absorption capacity of about 100,000 kJ to about 200,000 kJ.
 17. The apparatus of claim 10, wherein the at least one solid member is comprised of a nickel titanium alloy.
 18. The apparatus of claim 10, wherein the at least one solid member transforms from the first phase to the second phase at a temperature of about 60° F. to about 75° F.
 19. A system for absorbing and releasing heat, comprising: a plurality of solid members made of a material that undergoes a phase change from a first phase to a second phase, thereby absorbing heat from ambient air in contact with the solid members; one or more locking members that holds at least one of the solid members in the first phase, wherein the locking members can be selectively released at a predetermined time allowing the solid members to absorb heat from the ambient air; a chassis to hold the solid members in mechanical communication with the locking members; and a plurality of wheels physically coupled with the chassis to support the chassis, thereby allowing the system to be reversibly moved from a first preselected location wherein the ambient air is below about 60° F. to a second preselected location wherein the ambient air is above about 75° F.; whereby, in the first preselected location the solid members transition to the first phase, thereby releasing heat into the ambient air, and the solid members are held in the first phase by the locking members; and in the second preselected location one or more locking members can be selectively released to allow transition of at least one of the solid members to the second phase, thereby allowing the solid members to absorb heat from the ambient air. 